scholarly journals Spatial signals link exit from mitosis to spindle position

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Jill Elaine Falk ◽  
Dai Tsuchiya ◽  
Jolien Verdaasdonk ◽  
Soni Lacefield ◽  
Kerry Bloom ◽  
...  
Keyword(s):  
Spindle Pole ◽  
Mitotic Exit ◽  
Zone Model ◽  
Cytoplasmic Microtubule ◽  
Binucleate Cells ◽  
Spindle Pole Bodies ◽  
Mitotic Exit Network ◽  
Bud Neck ◽  
Competing Models ◽  
Spindle Position

In budding yeast, if the spindle becomes mispositioned, cells prevent exit from mitosis by inhibiting the mitotic exit network (MEN). The MEN is a signaling cascade that localizes to spindle pole bodies (SPBs) and activates the phosphatase Cdc14. There are two competing models that explain MEN regulation by spindle position. In the 'zone model', exit from mitosis occurs when a MEN-bearing SPB enters the bud. The 'cMT-bud neck model' posits that cytoplasmic microtubule (cMT)-bud neck interactions prevent MEN activity. Here we find that 1) eliminating cMT– bud neck interactions does not trigger exit from mitosis and 2) loss of these interactions does not precede Cdc14 activation. Furthermore, using binucleate cells, we show that exit from mitosis occurs when one SPB enters the bud despite the presence of a mispositioned spindle. We conclude that exit from mitosis is triggered by a correctly positioned spindle rather than inhibited by improper spindle position.

scholarly journals Evolutionary trade-offs between unicellularity and multicellularity in budding yeast

2018 ◽  
Author(s):  
Jennie J. Kuzdzal-Fick ◽  
Lin Chen ◽  
Gábor Balázsi
Keyword(s):  
Mitotic Exit ◽  
Fundamental Question ◽  
Bet Hedging ◽  
Evolutionary Transitions ◽  
Wild Yeast ◽  
Yeast Strains ◽  
Trade Offs ◽  
Mitotic Exit Network ◽  
Multicellular Organisms ◽  
Benefits And Costs

ABSTRACTMulticellular organisms appeared on Earth through several independent major evolutionary transitions. Are such transitions reversible? Addressing this fundamental question entails understanding the benefits and costs of multicellularity versus unicellularity. For example, some wild yeast strains form multicellular clumps, which might be beneficial in stressful conditions, but this has been untested. Here we show that unicellular yeast evolves from clump-forming ancestors by propagating samples from suspension after larger clumps have settled. Unicellular yeast strains differed from their clumping ancestors mainly by mutations in the AMN1 (Antagonist of Mitotic exit Network) gene. Ancestral yeast clumps were more resistant to freeze/thaw, hydrogen peroxide, and ethanol stressors than their unicellular counterparts, while unicellularity was advantageous without stress. These findings inform mathematical models, jointly suggesting a trade-off between the benefits and downsides of multicellularity, causing bet-hedging by regulated phenotype switching as a survival strategy in unexpected stress.

scholarly journals LATS1/WARTS phosphorylates MYPT1 to counteract PLK1 and regulate mammalian mitotic progression

2012 ◽  
Vol 197 (5) ◽  
pp. 625-641 ◽  
Author(s):  
Tatsuyuki Chiyoda ◽  
Naoyuki Sugiyama ◽  
Takatsune Shimizu ◽  
Hideaki Naoe ◽  
Yusuke Kobayashi ◽  
...  
Keyword(s):  
Dna Damage ◽  
Deoxyribonucleic Acid ◽  
Mitotic Exit ◽  
Dna Damage Checkpoint ◽  
Mitotic Progression ◽  
Myosin Phosphatase ◽  
G2 Checkpoint ◽  
Mitotic Exit Network ◽  
Kinase Screening

In the mitotic exit network of budding yeast, Dbf2 kinase phosphorylates and regulates Cdc14 phosphatase. In contrast, no phosphatase substrates of LATS1/WARTS kinase, the mammalian equivalent of Dbf2, has been reported. To address this discrepancy, we performed phosphoproteomic screening using LATS1 kinase. Screening identified MYPT1 (myosin phosphatase–targeting subunit 1) as a new substrate for LATS1. LATS1 directly and preferentially phosphorylated serine 445 (S445) of MYPT1. An MYPT1 mutant (S445A) failed to dephosphorylate Thr 210 of PLK1 (pololike kinase 1), thereby activating PLK1. This suggests that LATS1 promotes MYPT1 to antagonize PLK1 activity. Consistent with this, LATS1-depleted HeLa cells or fibroblasts from LATS1 knockout mice showed increased PLK1 activity. We also found deoxyribonucleic acid (DNA) damage–induced LATS1 activation caused PLK1 suppression via the phosphorylation of MYPT1 S445. Furthermore, LATS1 knockdown cells showed reduced G2 checkpoint arrest after DNA damage. These results indicate that LATS1 phosphorylates a phosphatase as does the yeast Dbf2 and demonstrate a novel role of LATS1 in controlling PLK1 at the G2 DNA damage checkpoint.

scholarly journals Order of function of the budding-yeast mitotic exit-network proteins Tem1, Cdc15, Mob1, Dbf2, and Cdc5

2001 ◽  
Vol 11 (10) ◽  
pp. 784-788 ◽  
Author(s):  
Sarah E. Lee ◽  
Lisa M. Frenz ◽  
Nicholas J. Wells ◽  
Anthony L. Johnson ◽  
Leland H. Johnston
Keyword(s):  
Budding Yeast ◽  
Mitotic Exit ◽  
Mitotic Exit Network

Human LATS1 Is a Mitotic Exit Network Kinase

2005 ◽  
Vol 65 (15) ◽  
pp. 6568-6575 ◽  
Author(s):  
John Bothos ◽  
Robyn L. Tuttle ◽  
Michelle Ottey ◽  
Francis C. Luca ◽  
Thanos D. Halazonetis
Keyword(s):  
Mitotic Exit ◽  
Mitotic Exit Network

scholarly journals The mitotic exit network

2003 ◽  
Vol 13 (8) ◽  
pp. R301 ◽  
Author(s):  
Geoffroy de Bettignies ◽  
Leland H. Johnston
Keyword(s):  
Mitotic Exit ◽  
Mitotic Exit Network

The Mitotic Exit Network: new turns on old pathways

2014 ◽  
Vol 24 (3) ◽  
pp. 145-152 ◽  
Author(s):  
Manuel Hotz ◽  
Yves Barral
Keyword(s):  
Mitotic Exit ◽  
Mitotic Exit Network
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